What problem does this address?

This comes out of assisting with #58855 (Footnotes).

The Gutenberg build script currently registers the various functions in the block library to replace their WordPress Core equivalent (ie, the version that has been committed to WordPress-Develop).

While working on the Footnotes CPT issue, I noticed that the WordPress Develop hooks aren't de-registered so will continue to run in addition to the Gutenberg hooks. Generally this is fine, if a little sub-optimal, as the Gutenberg hooks usually replace the markup generated by the WP-Dev hooks.

However, in some cases it can lead to unexpected behaviour when registering features for a block. As an example, modifying register_block_core_footnotes_post_meta() in Gutenberg will still run the unchanged code in WordPress-Develop.

What is your proposed solution?

Modify the build script to de-register the core block when running the plugin.

This will ensure any changes to a block's PHP file are reflected in the execution without interference from WordPress-Develop.

cc @gziolo @youknowriad (PR incoming but it's broken)